The perimeter of a rectangle is 400 meters. The length is 15 meters less than 4 times the width. Fin

Discussion in 'Calculator Requests' started by math_celebrity, Aug 21, 2016.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    The perimeter of a rectangle is 400 meters. The length is 15 meters less than 4 times the width. Find the length and the width of the rectangle.

    l = 4w - 15
    Perimeter = 2l + 2w

    Substitute, we get:
    400 = 2(4w - 15) + 2w
    400 = 8w - 30 + 2w
    10w - 30 = 400

    Add 30 to each side
    10w = 370

    Divide each side by 10 to isolate w
    w = 37

    Plug that back into our original equation to find l
    l = 4(37) - 15
    l = 148 - 15
    l = 133

    So we have (l, w) = (37, 133)
     

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